VIRGINIA, Minn. — Wiping away tears, Krista Swanson recalled the moment she was told her 11-month-old son had died in a fire at her Tower home.

A man carrying a clipboard told her while she was sitting in a vehicle at the fire scene, she said. She remembered she was concerned that if her son Bentley Koski had been in the house, her boyfriend's brother, Jesse Lee Bonacci-Koski, had also been there, because he wouldn't have left Bentley alone while babysitting him.

"It's a big blur. It's like it wasn't even real," she testified on Wednesday.

But Bonacci-Koski, 26, had left his nephew home alone on the morning of Aug. 2, 2017, and the house caught fire during his absence, killing Bentley while he "was trapped in that crib and completely dependent on his uncle," assistant county attorney Bonnie Thayer said during her opening statement in Bonacci-Koski's manslaughter trial Wednesday, Sept. 12.

Bonacci-Koski gave law enforcement differing reasons why he was away from the house — he left to use Wi-Fi or he left to go "get high," Thayer said. Whatever the reason, he had options that morning and he chose to leave Bentley alone, then chose to run — Bonacci-Koski allegedly stole a neighbor's vehicle and fled the scene — rather than tell authorities Bentley was in the home when he learned about the fire, she said.

Bonacci-Koski didn't know that morning was going to be the last time he saw Bentley, nor did he think that a fire would ignite and kill his nephew while he was gone, public defender J.D. Schmid said in his opening statement. Bonacci-Koski ran because he was on probation and he was scared, he said. He added that the trial isn't about whether Bentley's death is a tragedy or if Bonacci-Koski made mistakes that day.

"It's about whether he's guilty of manslaughter. He's not, because he didn't leave intending to put Bentley's life in danger," Schmid said. "The evidence will show that the fire killed Bentley."

Bonacci-Koski is charged with two felony counts of second-degree manslaughter, felony theft of a motor vehicle and gross misdemeanor fifth-degree possession of a controlled substance. His trial is expected to continue Thursday, Sept 13.

The State Fire Marshal's Office wasn't able to determine a cause of the fire, but extensive damage was found in the kitchen.

Multiple firefighters testified Wednesday that had they known there was an infant in the house when they arrived, they would have immediately attempted to reach the upstairs bedroom using a ladder. Instead, they worked to extinguish the fire on the first floor, finding Bentley upstairs in his crib about 45 minutes after they arrived.

"If we knew a person was there, we would have changed tactics," said Matthew Tuchel, the Breitung assistant fire chief.

In addition to videos of Bentley, photos were shown on Wednesday of the house's smoke-and-fire damaged interior, including a photo of Bentley's crib mattress blackened by soot except for a spot in the shape of the child.

Medical examiner Rebecca Asch-Kendrick testified cause of death was "inhalation of products of combustion."

Swanson said she and Bentley's father, Cody Koski, decided on Aug. 1 to spend a night away from home, and asked Bonacci-Koski, who was staying with them, to watch Bentley. Bonacci-Koski had babysat Bentley a few times before and Swanson said she felt comfortable leaving her son with him. She said she didn't believe Bonacci-Koski was under the influence of drugs when she asked him to babysit that night. She also said she didn't think she needed to tell him that he couldn't leave Bentley home alone.

"I know he loved him. I know he did," Swanson said.

Discovering the fire and Bentley

Bradley Matich, a Tower firefighter who lived next door, testified that he saw black smoke coming out of the house's windows about 7:40 a.m. Aug. 2. He called 911 and ran around the house, beating the walls to alert anyone inside. He didn't hear a response from inside and he didn't see any vehicles parked at the house to indicate that someone was home, he said. He tried to go in the house to check, but the smoke was too thick.

Bentley was found during the firefighters' mop up after they extinguished the fire. Lance Dougherty, the Tower assistant fire chief, saw the crib when they entered the bedroom and said he couldn't tell if he was seeing a child or a doll when he looked in the crib. When he realized it was a child, he immediately brought him outside, handing him to Tuchel. After that, Dougherty said, "I wanted to shake off what we had just discovered."

Tuchel, who is also an EMT with Tower Ambulance, began CPR on Bentley, even though it was obvious that Bentley had been in the house the entire time. It's what he's trained to do, he said.

"You've got to give that child a chance. We all gave that child as much as we could to bring him back," Tuchel said. "We never give up hope."